all_dec_args = {}
    for arg_name, arg_value in zip(_COMPOSITE_ARG_LIST, compose_dec[0].args):
      all_dec_args[arg_name] = self.visit(arg_value)

    kw_dec_args = dict([self.visit(kw) for kw in compose_dec[0].keywords])

    if all_dec_args.keys() & kw_dec_args.keys():
      raise KeyError('More arguments than expected.')

    all_dec_args.update(kw_dec_args)